Working on a Peterbilt

[OHMS LAW]

With a cummins, and Eaton manual trans. Came to a stopping point.on the flywheel I have 12 pt bolts. Now my question is are they 13/16 or 21mm. The 13/16 had to be tapped on but fit snug. The 21mm slid on there but with the impact it kinda chewed it up on a few test bumps with the impact.

Anyone have any idea or input. Thanks a lot.

Also first time I’m balls deep in a big truck.

Also I thought I took a pic. Sorry guys

 

[blaker]

21 is what I ues

 

[Nor'Easter]

Pete has used Cummins since the 40s. Older engines would have SAE hardware, newer would be metric. Not sure when the changeover occurred, but a year would help.

Flywheels should be hand torqued.

 

[bcschief]

IS series engines would be metric

Brian

 

[Dieselhammer]

How old are we talkin? if its an ISX its 21mm, if its old enough to be say a big cam cummins or the like it'll be standard. Either way, if you can beat a 13/16" on snug with no slop, why not use it?

 

[OHMS LAW]

Sorry guys been busy the last few days. It’s a 11 with the isx15. Had a 21mm impact cornwell socket. It just about looks like my late grandfathers teeth or lack there of. It destroyed one of the bolts. So I whipped out the torch and got it nice and red hot. Then hammered a 13/16 and it zipped right out. Did the same for the rest. Got tired of fooling with it.

So got the flywheel off and sent it for resurfacing, now to replace the flywheel housing, gasket and rear main. Also the pilot bearing since I took a torch to it.